182 
THE GEOLOGIST. 
hour nearly as it rose above the sea, save iu the effects of denudation 
and atmospheric weathering of long past ages, and in its thin crust of 
grey lichens, and its mantle of scanty herbage, which thus may grow 
where Coal and Tertiary plants during former eras found scanty 
sustenance. 
In om* own isles, all that remains of the first land are the old 
gneissic regions in the Orkneys, and in the north of Scotland, near 
Cape Wrath ; and these we have questioned hitherto in vain for any 
traces of living things. All their secrets are still firmly locked up in 
their compact, crystalline, adamantine breasts. 
Whether any traces of the old gneissic rock — the equivalent of the 
Laureutian Group — are yet to be found beneath the mountain-masses 
of the primitive sediments formed upon its shores (our Cambrian 
rocks, the equivalents of the American Huronian group), further 
researches, or rather, perhaps, future excavations or borings, can alone 
determine. Probably, however, the original lands, on the shores of 
which the Welsh and Irish Cambrian deposits were formed, have sunk 
beneath the ocean with that old great western continent, the debris of 
which remains iu the Upper Palteozoic and Triassic deposits. 
We must, then, for the jjresent, lea.ve the nature and conditions of 
the first land in that obscurity in which ages of time have enveloped 
it, and turn to the earliest stratified deposits on its shore, — our 
Cambrian or " bottom-rocks," — for our first intelligible data of the 
earth's early history. 
Some portions of these primary sediments remain in Caernarvon. 
The grits, 8,000 feet thick, of Harlech, in North Wales, belong to this 
age ; and equivalent rocks rise from beneath the Lower Silurian near 
St. David's Head, in South Wales. Vast masses are also found at 
Bray Head, in Ireland, and a patch also probably occurs at Charnwood 
Forest, in Leicestershire, although the last is possibly only an altered 
Silurian deposit. 
For a long time it was believed, from their crystalline character, 
that the schists, quartzose, and felsjiathic rocks of the Isle of Anglesea 
were more ancient than any of the strata of the adjacent mainland. 
But tins is not the case, for it is now well ascertained that they are 
but altered Silurian beds^ and that the rocks from which they, as well 
